This is the sort of functionality that has been made available by numerous text editors and IDEs for numerous programming languages for many, many years now.
It's somewhat unusual to see how so many in the JavaScript and web development communities can get so excited about catching up to where basically everybody else was decades ago. It'd be one thing if JavaScript and web development were new creations, but they're not.
While this may be useful in some cases, it's surely not "amazing".